Insulin Dosing for Diabetic Ketoacidosis (DKA)
For adult patients with DKA, the recommended insulin dosing is a continuous intravenous regular insulin infusion at an initial rate of 0.1 units/kg/hour without an initial bolus dose. 1, 2
Initial Insulin Administration
- Continuous intravenous regular insulin infusion is the standard of care for critically ill and mentally obtunded patients with DKA 1
- Start with continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus 1, 2
- IV bolus insulin is generally not recommended for DKA treatment as it provides no significant benefit and may increase risk of complications 3
- Continue insulin therapy until resolution of ketoacidosis (pH >7.3, serum bicarbonate ≥18 mEq/L, and anion gap ≤12 mEq/L) regardless of glucose levels 1
Monitoring and Titration
- Monitor blood glucose hourly or more closely as needed, with the goal of gradually reducing blood glucose by 50-100 mg/dL per hour 4
- When serum glucose reaches 250 mg/dL, change IV fluids to include dextrose (D5W with 0.45-0.75% NaCl) while continuing insulin therapy to resolve ketosis 1
- Do not discontinue insulin therapy prematurely when glucose levels fall below 200-250 mg/dL; instead, add dextrose to the hydrating solution while continuing insulin infusion 5
- Draw blood every 2-4 hours to determine serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1, 2
Special Populations
- For pediatric patients, the recommended IV insulin infusion rate is lower: 0.05-0.10 unit/kg per hour 4
- For neonates, use an even lower IV infusion rate of 0.05 unit/kg per hour 4
- Asian patients may be more insulin-sensitive and benefit from a lower initial insulin dose of 0.05 units/kg/hour 6
- For mild or moderate uncomplicated DKA in stable patients, subcutaneous rapid-acting insulin analogs (0.25-0.50 unit/kg per dose) combined with aggressive fluid management can be as effective as intravenous insulin 4, 1
Transition to Subcutaneous Insulin
- When DKA resolves (glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L) and the patient can eat, transition to subcutaneous insulin 1, 5
- Administer basal insulin 2-4 hours before stopping the intravenous insulin to prevent recurrence of ketoacidosis and rebound hyperglycemia 1, 2
- Start a multiple-dose schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 2
Common Pitfalls to Avoid
- Premature termination of insulin therapy before complete resolution of ketosis can lead to recurrence of DKA 5
- Interruption of insulin infusion when glucose levels fall is a common cause of persistent or worsening ketoacidosis 5
- Failure to add dextrose to IV fluids when blood glucose falls below 250 mg/dL while continuing insulin therapy 1
- Inadequate monitoring of potassium levels during insulin therapy, which can cause hypokalemia 1, 5
Alternative Approaches
- Very-low-dose insulin protocols (0.025-0.05 units/kg/hour) have been studied and may be effective with fewer complications in certain populations, but standard dosing remains the recommendation from major guidelines 7, 8
- In resource-limited settings where ICU beds are scarce, protocols using subcutaneous rapid-acting insulin analogs at 0.15 U/kg every 2-3 hours have been used successfully 9
Remember that appropriate fluid and electrolyte therapy is essential alongside insulin when treating DKA, with close monitoring of clinical and biochemical parameters throughout treatment 4, 1.